1. Field of the Invention
The present invention relates generally to a method of medical diagnostics of fluids, and, more particularly, to an apparatus for carrying out such methods utilizing the acousticomechanical impedance (AMI) characteristics associated with the properties of drying droplets of biological fluids.
2. Description of the Related Art
A sessile drop is a specific physical object. The initial shape of a drop is a function of its physical properties and substrate nature. In the same environment the following factors play a significant role in the dynamics of the drop drying process: surface tension, wettability, viscosity, inner structure, dispersion of colloids, heat conductance, ionic force, gel-forming substances, and cover skin density. Even the slightest variation in the composition of a liquid leads to the total change in these parameters during drop drying.
In recent years the effect of a drying drop as a natural model of self-organizing system with an extensive set of process variations has become a subject of an increasingly active research interest worldwide. The diagnostics in this research relied on the morphological structures seen with a microscope in dried droplets of biological liquids, and on their verbal description. One approach provides diagnostic information drawn all through a droplet drying process as described in U.S. Pat. No. 6,874,357, issued in the name of Yakhno et al and incorporated by reference herein as if fully rewritten. The use of a subjective characterization of a drying drop of multicomponent fluid is described. The present invention is devoted to the medical applications utilizing these previous teachings.
In medicine, bodily fluids are often subjected to analysis where the levels of proteins, macromolecules and other natural constituents of bodily fluids are measured. The absence or presence of pathogens is often examined as well. These analyses often measure the level of formation of a colored product. Alternatively, specific antibodies against proteins or pathogens can be utilized. A unique kit of reagents is necessary for each such test, and often a separate machine is used for only a limited number of laboratory tests. This greatly increases the expense of body fluid analysis.
Of particular interests is blood serum, but other biological liquids are anticipated as useful, including urine and saliva. A dried droplet of serum from a healthy person is a central-symmetry figure and resembles a rosette owing to a slightly concave shape and regular arch-like cracks. The peripheral zone is mostly protein and in the center there are salt structures. This symmetry is disturbed in a diseased person, the structuring character changes, and dried drops take atypical forms. It has been established that there is a relation between the nosology of a disease and the qualitative changes in a drop shape, which is used as an additional criterion in medical diagnostics. The central zone in dried drops of different biological liquids from the same person is of the same morphological type. The character of the central zone structuring in dried drops depends on their viscosity: liquids with a lower viscosity factor form well organized clear-interface structures.
Diagnostic assays using saliva are a relatively new but growing technology. The FDA approved the first HIV test based on saliva rather than blood. Besides, a new technology is being actively developed currently, the HIV Urine Test, which was also approved by the FDA.
The need exists for a method in which a plurality of analyses of the contents of body fluid could be performed using one device or machine. In the manufacturing and storage of materials, such as fossil fuels, and pharmaceuticals, quality control must be assured, to ascertain that the materials manufactured have not deteriorated in the course of manufacture or with the passage of time. Chromatography is often utilized, and the specific reaction conditions for each material undergoing analysis must be found. The need exists for a simple method in which little calibration need be performed before analysis of highly dissimilar materials.
Consequently, a need has been felt for providing an apparatus and method based on two phenomena: nonlinear dynamic processes in drying drops of biological fluids; and, a possibility of utilizing these processes by means of a diagnostic method, test or device developed for this task.